Boat construction



March 15, 1966 s. STOCKING ETAL BOAT CONSTRUCTION 2 Sheets-Sheet 1 FiledOct. 27. 1964 INVENTOR. STANNARD S TUC KING J OHM C. STOCKING ATTOPNEMarch 1966 s. STOCKING ETAL BOAT CONSTRUCTION 2 Sheets-Sheet 2 FiledOct. 27, 1964 INVENTOR. STANA/ARD swam/a JOHN c. swam/v5 BY 4M2,

7km? ATTORNEK? United States Patent 3,239,856 BOAT CONSTRUCTION StaunardStocking, 3 Oliver St., South Norwalk, Conn., and John C. Stocking, 190Waite St., Hamden, Conn. Filed Oct. 27, 1964, Ser. No. 406,825 4 Claims.(Cl. 9-6) The present invention relates to boats and more particularlyto an improved hull construction for small boats which may be rowed,sailed, or motor driven.

It is a common practice to moor a boat at a permanent mooring at somedistance from the shore and then use a smaller boat for transportationfrom the shore to the mooring. One form of tender used for this purposeis a pram of short length and having flat ends or transoms to increaseits beam. Also, other forms of small boats in the range of six feet tosixteen feet in length are used for rowing, sailing and motor propulsionby inboard or outboard motors and may have round, fiat or V-shapedbottoms. Such boats, and especially the smaller ones such as prams, areeasily tipped and, therefore, are apt to tip over completely or cause aperson in the boat to lose his balance and fall from the boat into thewater. Furthermore, such boats do not tow nor point well, but insteadare apt to pitch and yaw from side to side.

One of the objects of the present invention is to provide a boat of thetype indicated with an improved hull construction for materiallyincreasing the stability of the boat against tipping and capsizing.

Another object is to provide an improved construction in a boat toresist yawing while in motion either when propelled by oars or motor, orwhen towed.

Another object is to provide a boat of the type indicated with a doublebottom unsinkable construction without sacrificing otherwise usefulspace,

Still another object is to provide an improved hull construction for aboat which is of relatively simple and compact construction, economicalto manufacture and one which provides maximum stability and minimum dragwhen moving through the water at normal speeds.

These and other objects will become more apparent from the followingdescription and drawings in which like reference characters denote likeparts throughout the several views. It is to be expressly understood,however, that the drawings are for the purpose of illustration only andare not a definition of the limits of the invention, references beinghad for this purpose to the appended claims.

In the drawings:

FIGURE 1 is a perspective view of a small boat incorporating the novelfeatures of the present invention and showing the spaced sponsonsdepending from the sides of the hull at the stern of the boat.

FIGURE 2 is a side elevational view of the boat illustrated in FIGURE 1and showing its attitude with respect to the water line and the sponsonsextending forwardly from the stern and merging with the V -shaped bottomat a location greater than one-half the length of the boat from thestern.

FIGURE 3 is a plan view of the boat showing the location of thesponsons, the three centers of buoyancy and drag and the straight linesparallel to the centerline of the boat formed by the ledges at the inneredges of the sponsons.

FIGURE 4 is a transverse sectional view taken on line 4-4 of FLGURE 3 toshow the V-shaped form of the hull forwardly of the sponsons.

FIGURE 5 is a transverse sectional view taken on line 5-5 of FIGURE 4 toshow the Vshaped bottom and spaced sponsons at the sides of the boat.

FIGURE 6 is a transverse sectional view taken on line 3,239,856 PatentedMar. 15, 1966 66 of FIGURE 3 to further show the contour of the bottomof the boat adjacent the stern.

FIGURE 7 is a reproduction of a photograph of the boat illustrated inFIGURE 1 showing the stability of the boat with a person standing at oneside, amidship, and holding an outboard motor.

FIGURE 8 is a diagrammatic view of the boat showing the forces acting onthe boat tending to cause it to move in a straight line without yawing.

FIGURE 9 is a perspective view of the bottom of a boat of modifiedconstruction in which the sponsons incline inwardly toward each otherfrom the sides of the boat.

FIGURE 10 is a perspective view of a further modified constructionshowing the sponsons of triangular shape and having keel fins projectingfrom the apexes of the sponsons.

FIGURE 11 is a perspective view of the bottom of a boat of furthermodified construction in which the V- shaped bottom extends throughoutthe length of the boat with a depending fin adjacent the stern and fiatbottomed sponsons at either side of the curved surfaces therebetween.

FIGURE 12 is a perspective view of a boat similar to the one shown inFIGURE 9 but of modified construction having flat bottomed sponsons withdepended fins.

FIGURE 13 is a perspective view of a boat having a bottom of still moremodified construction in which the sponsons are curved with dependingfins. The invention resides in providing spaced sponsons depending fromthe sides of a boat which extend forwardly from the stern a distancegreater than one-half the length of the boat and which merge with thesides and bottom of the boat. This construction provides three majorcenters of displacement at the sides and bow of the boat about which theboat is supported. These three centers of support form the apexes of anequilateral triangle having a base line extending across the boatadjacent the stern and sides extending from the ends of the base lineforwardly and toward the other point on the centerline of the boatadjacent its bow. The triangle formed between the three points ofsupport is bisected by the centerline of the boat which extends at rightangles to the base line of the triangle. These three centers ofdisplacement remain substantially constant for all conditions of loadingwhen motionless and conditions of speed when moving, and in addition,provide a tripod for supporting the boat with greater stability aboutthe loading, boarding and working areas of the boat. The centers ofbuoyancy at the ends of the base line of the triangle provide side toside stability against rocking and together with the point on thecenterline of the boat provide fore and aft stability against pitching.

Furthermore, the sponsons are so formed as to provide ledges projectingdownwardly from the bottom of the boat in a direction parallel to thecenterline thereof and act as skeg keels to cause the boat to moveforwardly in a straight line when towed or propelled by oars, sail or amotor. Also, the three centers of buoyancy constitute three centers ofdrag to act against the forces tending to cause the boat to yaw as itmoves forwardly through the water.

In addition, the improved construction provides a double bottom havingan inner floor and an outer shell between which buoyant materials of lowspecific gravity such as cork, plastic foam, etc. are placed to providea flat floor deck and leaving all of the space between the sidesavailable for use. The buoyant materials are bonded to both the floorand outer shell to provide a hull of considerable rigidity and strengthwhich lends itself readily to molded plastic of fiberglass construction.

However, the bottom may be made of inner and outer sheets of plywoodcovered with fiberglass or of sheets of plywood only with appropriatestringers and or ribs to which the floor and outer shell are fastened.

The use of spaced sponsons beside providing stability about the centersof buoyancy also adapts the boat to plane on the surface of the water atrelatively low speed without sacrifice of stability since the planingsurfaces are widely spaced. It is well recognized that boats equippedwith planing surfaces are for many purposes superior to conventionalboats since at planing speeds displacement is minimized and dragproportionately reduced. The sponsons of the present invention providesuch planing surfaces as well as increasing the stability againsttipping, pitching and yawing.

For purposes of illustration the invention is shown applied to a pramhaving flat ends to increase its beam, but it is to be understood thatthe invention can be used to great advantage in any small boat having alength in the range of six feet to sixteen feet with hulls of variousshapes, whether it be used as a row boat, motor boat or sail boat. Thepram as shown in FIGURES l to 8 comprises sides 2 and 3, front and reartransoms 4 and and a bottom 6. The bottom 6 may be fiat, rounded orV-shaped to produce a greater displacement, and instead of a flattransom at the front end, the sides and bottom may be continued as shownin dotted and dash lines in FIGURE 3 to form a rounded or pointed bow.As thus far described the pram is of conventional construction.

In accordance with the present invention, spaced sponsons 7 and 8 dependfrom the bottom 6 of the boat and extend from the stern transom 5forwardly for a distance greater than one-half the length of the boat,see FIGURE 2. Preferably the sponsons 7 and 8 extend from the stern to apoint about two-thirds the length of the boat. The bottom 6 between thesponsons 7 and 8 is a V-shape, but with the angle decreasing from thestern toward the bow, see FIGURES 4 to 6. The forward end of thesponsons 7 and 8 merge with the V-shaped bottom 6 at their inner edgesand gradually curve upwardly until they merge with the bottom from theinner edges outwardly, see FIGURE 2.

As shown most clearly in FIGURES 5 and 6 the sponsons 7 and 8 are ofrectangular shape in cross section in the illustrated embodiment andhave outer and rearward edges 10, 11 and 12, 13 formed as continuationsof the sides 2 and 3 and rear transom 5 below the floor deck 9. Thebottom of the sponsons 7 and 8 are flat surfaces which incline upwardlyas they extend forwardly from the stern. Thus, the sponsons 7 and 8 havetheir greatest depth below the floor deck 9 at the stern and are ofgradually decreasing depth along their length until they merge with theV-shaped bottom 6 by gradually changing from fiat surfaces to theV-shaped bottom as shown most clearly in FIGURE 2. The inner edges ofthe sponsons 7 and 8 terminate in ledges 14 and 15 extending upwardly tomerge with the V-shaped bottom 6 as shown most clearly in FIGURES 5 and6. Ledges 16 and 17 are filets between the flat bottoms 14 and 15 of thesponsons 7 and 8 and the V-shaped bottom 6 and the ledges graduallydecrease in height from the stern toward the bow in accordance with thedepth of the sponsons. As will be observed from FIGURES 3, 5 and 6 theledges 16 and 17 are spaced from each other and from the centerline ofthe boat and extend in straight lines parallel to the centerline.

The boat has a double bottom construction comprising the floor deck 9and an outer shell 18 and the sponsons 7 and 8 are formed by ahomogeneous body of a buoyant material 19, such as cork, plastic foam,or the like, be tween the floor deck and shell. The buoyant material 19is bonded to the floor deck 6 and outer shell 18, as by a thermosettingplastic, to produce a rigid and strong construction. Furthermore, thisconstruction provides an unsinkable boat because of the buoyancy of thematerial 19 built into the double bottom of the hull. The resultingstructure as shown most clearly in FIGURES 4 to 6 has the sponsons 7 and8 projecting below the V-shaped bottom 6 adjacent the sides thereof andthe sponsons are of generally rectangular shape in cross section anddecrease in depth from the stern transom 4 forwardly for a distancegreater than one-half the length of the boat where they gradually mergewith the V-shaped bottom 6. For example, one boat made in accordancewith the present invention was eight feet long, four feet wide with eachsponson six inches wide at the stern and projecting downwardly fourinches below the bottom and of gradually decreasing height andincreasing width from the stern forwardly and terminating at a distanceof five feet from the stern.

A boat of this construction produces three centers of displacement andtherefore buoyancy. Two of these centers of buoyancy are located at thepoints B and C, as illustrated in FIGURES 2 and 3, while the third pointA is located on the centerline of the boat forwardly of the sponsons 7and 8. These three points A, B and C form, in effect, a triangular areawhich is bisected by the centerline of the boat. When the boat is loadedwithin this triangular area it has been found to be very stable againsttipping as compared with boats of similar dimensions with a conventionalbottom construction. For example, FIG- URE 7 is a photolithographedreproduction of a photograph showing one of the inventors standingadjacent the point B in the pram and holding an outboard motor withoutany substantial tipping of the boat. It is believed that the stabilityof the boat against rocking is due to the fact that loading of the boatin the triangular area between the points A, B and C will produce'agreater displacement by the sponson at opposite sides of the centerlinethan occurs between the sponsons so that the center of buoyancy does notshift as the boat is moved downwardly into the water, but instead, thethree centers of displacement and buoyancy A, B and C remainsubstantially constant. For example, any loading between the points A, Band C will produce a greater displacement of water in the areasurrounding the points A, B and C than at any point therebetween and theforce of the load at one point will be distributed to the other centers.Also, the displacement and buoyancy resulting from loading isdistributed around the three centers A, B and C to provide stabilityagainst fore and aft pitching. Whatever the reasons, the newconstruction as described above produces a greater stability in smallboats against rocking and pitching.

Furthermore, the construction of the sponsons 7 and 8 with spaced ledges16 and 17 at the inner edges extending in straight lines parallel toeach other and the centerline of the boat increases the resistance ofthe boat to yawing when it is being propelled either by oars, by sailsor by motor. It is believed that the reasons for this resistance toyawing is that the parallel ledges 16 and 17 act as keels resistingmovement in any direction except in the forward direction of the boat.The points B and C constituting centers of displacement and buoyancyalso constitute centers of drag because these points are where the boatis supported against the action of gravity when propelled. The forcesacting on the points B and C on the bottom of applicants boat when ittends to yaw are illustrated in FIGURE 8. If the boat tends to yaw tothe right as indicated by the centerline of the boat with respect to thedirection in which it is propelled as indicated by the horizontal lineD, a force couple is produced around said line of direction D at thepoints B and C. The drag produced on the points B and C would besubstantially the same, but the moment arm M between the drag point Band the line of direction D is shorter than the moment arm M-l actingbetween the drag point C and the line of direction of the boat. Thus asthe product of the force and moment arm M-l is greater than the productof the force and moment arm M, the resulting force tends to rotate theboat in a counterclockwise direction until the centerline of the boatcorresponds with the line of direction D. If the boat tends to yaw tothe left the reverse situation would exist. The only equilibriumposition where the forces acting on the points B and C are equal andopposite is when the centerline of the boat coincides with its line ofdirection D. Applicants improved construction, therefore, in addition toincreasing stability against rocking and pitching also increases thestability of the boat against yawing.

In addition to increasing the stability of the boat against rocking,pitching and yawing, the fiat bottoms 14 and 15 of the sponsons 7 and 8provide planing surfaces on which the boat rides when propelledforwardly either by oars, sails or a motor. A forward force applied tothe boat will cause it to ride up on the surface of the water to ahigher level than when the boat is motionless. The reason for this isthe tendency of the inclined planes formed by the flat bottoms 14 and 15of the sponsons 7 and 8 to ride out of the water. As the area of thebottom 6 of the boat in contact with the water decreases as it planes,the resistance to forward motion decreases. The centers of the forcesacting on the bottom of the sponsons 7 and 8 are then located at pointsB and C and act as centers of drag when the boat is propelled atmoderate speed.

FIGURE 9 illustrates a boat of modified construction incorporating thenovel features of the present invention. In FIGURE 9 the bottom of theboat has a V-shaped construction 24 at its forward end for approximatelyonethird of its length and an inverted V-shaped construction 25 for therearward two-thirds of its length. The sponsons 26 and 27 projectdownwardly as continuations of the sides 28, 29 and transom 30 the sameas in the construction illustrated in FIGURES 1 to 8, but the sponsonsincline inwardly from the edges to form the inverted V-shaped section25. Each of the sponsons 26 and 27 has a fin 31 and 32, respectivelydepending from the outer edge thereof.

FIGURE illustrates a further modified construction having a V-shapedbottom section adjacent its forward end and an inverted V-shaped sectionrearwardly of the V-shaped section the same as in FIGURE 9. The sponsons35 and 36, however, are of generally triangular shape in cross-sectionhaving apexes 37 and 38 inwardly from the sides of the boat. Fins 39 and40 depend from the apexes 37 and 38 of the sponsons 35 and 36 adjacentthe rearward ends thereof.

FIGURE 11 illustrates a further modified construction in which flatbottomed sponsors 43 and 44 depend from the sides of the boat with aV-shaped bottom section therebetween the same as the sponsons 7 and 8and V- shaped bottom 6 in the boat illustrated in FIGURES 1 to 8.However, between the inner edges of the sponsons 43 and 44 and theV-shaped center portion 45 of the boat the bottom has curved surfaces 46and 47. In addition a fin keel 48 projects downwardly from the V-shapedcenter portion of the hull adjacent its rearward end.

FIGURE 12 illustrates a further modified construction having a reverseV-shaped bottom as in the construction illustrated in FIGURES 9 and 10,but with flat bottomed sponsons 50 and 51 as illustrated in FIGURES 1 to8 and fins 52 and 53 depending from the center of the flat bottomsponsons.

FIGURE 13 illustrates a still further modified construction in which thesponsons 55 and 56 are of a curved contour with depending fins 57 and 58and a reversely curved section 59 between the curved sponsons.

It will now be observed that the present invention provides an improvedhull construction for small boats that materially increase the stabilityof the boat against tipping, pitching and yawing. It will also beobserved that the present invention provides an unsinkable boat with adouble bottom construction without sacrificing otherwise useful space inthe boat. It will still further be observed that the invention providesan improved hull construction for a boat which is of relatively simpleand compact construction that may be economically manufactured, and onewhich provides maximum stability and minimum drag when moving throughthe water at normal speeds.

While several forms of construction are herein illustrated and describedit will be understood that further changes may be made in theconstruction and arrangement of elements without departing from thespirit or scope of the invention. Therefore without limitation in thisrespect the invention is defined in the following claims.

We claim:

1. A boat having sides, a V-shaped bottom extending throughout itslength and of a gradually decreasing angle from the stern to the forwardend, sponsons depending from the sides of the boat in spaced relation atopposite sides of its centerline and extending forwardly from the sternfor substantially two-thirds the length of the boat, said sponsonshaving flat surfaces at the bottom tapering from a maximum depth at thestern until they merge with the V-shaped bottom, the inner edges of thesponsons being parallel to the centerline of the boat and forming ledgesmerging with the V-shaped bottom, said sponsons at the stern andV-shaped bottom at the forward end of the boat providing threesubstantially constant centers of buoyancy and drag at the apexes of anequilateral triangle bisected by the centerline of the boat whereby tostabilize the boat against tipping, pitching and yawing when propelledand towed.

2. A boat in accordance with claim 1 having a double bottom comprisingan inner floor and outer shell around the sponsons, and the spacebetween the inner floor and outer shell containing a buoyant material.

3. A boat in accordance with claim 2 in which the inner floor and outershell are formed of fiberglass coated with a thermo-setting plastic.

4. A boat in accordance with claim 1 having fiat ends connected to thebottom and sides.

References Cited by the Examiner UNITED STATES PATENTS 1,189,227 7/1916Baker 114-62 1,898,876 2/1933 Heljesson 114-66.S 2,126,304 8/1938 Apelet al. 11466.5 2,367,323 1/1945 Apel 11466.5 2,397,683 4/1946 Nelson114-665 3,007,208 11/1961 Urban 9-6 FERGUS S. MIDDLETON, PrimaryExaminer.

1. A BOAT HAVING SIDES, A V-SHAPED BOTTOM EXTENDING THROUGHOUT ITSLENGTH AND OF A GRADUALLY DECREASING ANGLE FROM THE STERN TO THE FORWARDEND, SPONSONS DEPENDING FROM THE SIDES OF THE BOAT IN SPACED RELATION ATOPPOSITE SIDES OF ITS CENTERLING AND EXTENDING FORWARDLY FROM THE STERNFOR SUBSTANTIALLY TWO-THIRDS THE LENGTH OF THE BOAT, SAID SPONSONSHAVING FLAT SURFACES AT THE BOTTOM TAPERING FROM A MAXIMUM DEPTH AT THESTERN UNTIL THEY MERGE WITH THE V-SHAPED BOTTOM, THE INNER EDGES OF THESPONSONS BEING PARALLEL TO THE CENTERLINE OF THE BOAT AND FORMING LEDGESMERGING WITH THE V-SHAPED BOTTOM, SAID SPONSONS AT THE STERN ANDV-SHAPED BOTTOM AT THE FORWARD END OF THE BOAT PROVIDING THREESUBSTANTIALLY CONSTANT CENTERS OF BUOYANCY AND DRAG AT THE APEXES OF ANEQUILATERAL TRIANGLE BISECTED BY THE CENTERLINE OF THE BOAT WHEREBY TOSTABILIZE THE BOAT AGAINST TIPPING, PITCHING AND YAWING WHEN PROPELLEDAND TOWED.